package com.wu.datastructure.stack;

/**
 * @version v1.0
 * @ProjectName learning-java
 * @ClassName ArraySk
 * @Description TODO 数组工具类
 * @Author wudl
 * @Date 2020/12/2 17:35
 */

public class ArraySk<E> {

    private E[] data;
    private int size;

    /**
     * 通过构造函数对组进行初始化
     *
     * @param capacity
     */
    public ArraySk(int capacity) {
        data = (E[]) new Object[capacity];
        size = 0;
    }

    /**
     * 一个无参构造函数
     */
    public ArraySk() {
        this(10);
    }

    /**
     * 返回数组中的个数
     *
     * @return
     */
    public int getCapacity() {
        return data.length;
    }

    /**
     * 返回数组中的元素
     *
     * @return
     */
    public int getSize() {
        return size;
    }

    /**
     * 返回数组是否为空
     *
     * @return
     */
    public boolean getEmpty() {
        return size == 0;
    }

    public void addLast(E e) {
        add(size, e);
    }

    public void addFirst(E e) {
        add(0, e);
    }

    public void add(int index, E e) {
        if (size == data.length) {
            throw new IllegalArgumentException("Add failed. Array is full.");
        }
        if (index < 0 || index > size) {
            throw new IllegalArgumentException("Add failed. Require index >= 0 and index <= size.");
        }

        for (int i = size - 1; i >= index; i--) {
            data[i + 1] = data[i];
        }
        data[index] = e;
        size++;

    }

    /**
     * 根据索引信息 获取数组值
     *
     * @param index
     * @return
     */
    public E get(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("Get failed. Index is illegal.");
        }
        return data[index];
    }

    public void setData(int index, E e) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("Get failed. Index is illegal.");
        }
        data[index] = e;
    }

    // 查找数组中是否有元素e
    public boolean contains(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e)) {
                return true;
            }
        }
        return false;
    }

    // 查找数组中元素e所在的索引，如果不存在元素e，则返回-1
    public int find(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e)) {
                return i;
            }
        }
        return -1;
    }

    // 从数组中删除index位置的元素, 返回删除的元素
    public E remove(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("Remove failed. Index is illegal.");
        }
        E ret = data[index];
        for (int i = index + 1; i < size; i++) {
            data[i - 1] = data[i];
        }
        size--;
        data[size] = null; // loitering objects != memory leak
        if (size == data.length / 2) {
            resize(data.length / 2);
        }
        return ret;
    }

    // 从数组中删除第一个元素, 返回删除的元素
    public E removeFirst() {
        return remove(0);
    }

    // 从数组中删除最后一个元素, 返回删除的元素
    public E removeLast() {
        return remove(size - 1);
    }

    // 从数组中删除元素e
    public void removeElement(E e) {
        int index = find(e);
        if (index != -1) {
            remove(index);
        }
    }

    public E getLast() {
        return get(size - 1);
    }

    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append(String.format("Array: size = %d , capacity = %d\n", size, data.length));
        res.append('[');
        for (int i = 0; i < size; i++) {
            res.append(data[i]);
            if (i != size - 1) {
                res.append(", ");
            }
        }
        res.append(']');
        return res.toString();
    }

    // 将数组空间的容量变成newCapacity大小
    private void resize(int newCapacity) {

        E[] newData = (E[]) new Object[newCapacity];
        for (int i = 0; i < size; i++) {
            newData[i] = data[i];
        }
        data = newData;
    }
}
